The population in 1986 (extrapolated from the 1982 census) was estimated at 2.7 million. The cases were people with unintentional or intentional injuries sustained from December 1985 to December 1986 that resulted in death or required hospitalization. Public and private hospitals participating in the study were asked to complete a questionnaire for each injury case that required admission. The questionnaire included queries about demographic information and time and place, cause, origin, and clinical nature of the injury. Causes and clinical nature of the injuries were coded according to a classification system designed specifically for the study. All 21 public hospitals and 38 of the 43 private hospitals contributed to the study (Tiret et al., 1989).
From 1985 to 1986, there were 391 deaths and 2,116 hospital admissions due to head trauma; the case-fatality rate was 4%. In the nonfatally head-injured patients, 80% of the head injuries were classified as mild, 11% moderate, and 9% severe (Tiret et al., 1990). The overall annual incidence was 281 per 100,000, and the annual mortality was 22 per 100,000 (Tiret et al., 1990).
Masson and colleagues (1996) assessed the effects of cognitive, behavioral, and somatic impairments on disability and recovery after TBI. The study population included 231 TBI patients 5 years after injury and 80 lower-limb–injured controls. Sixty-four lower-limb–injured patients and 176 TBI patients were assessed. The severity of the head injuries was defined as severe if a patient had a Glasgow Coma Scale (GCS) score of 8 or less for at least 6 hours in the first 24 hours after injury; moderate if the patients had one of the following, a GCS score of 8 or less between 1 and 6 hours, a GCS score of 9–12 on the first day after injury, an abnormal computed tomography scan, or a need for a neurosurgical procedure; and minor if neither of those categories was appropriate. A number of complaints were more commonly reported in TBI patients than in the lower-limb–injured patients, such as headache (OR, 4.6), memory problems (OR, 4.01), dizziness (OR, 3.35), anxiety (OR, 6.11), and sleep disturbance (OR, 3.10). Regarding mild, moderate, and severe TBI, there was no significant difference in the prevalence of headaches (44%, 54%, 44%), anxiety (47%, 49%, 63%), and dizziness (33%, 37%, 26%) among the three TBI severity groups, respectively. Mental impairments were reported frequently in patients with severe TBI (18–40% of patients); however, most impairments in patients with minor and moderate TBI were related to associated injuries.
Masson and colleagues (1997) conducted a study to assess long-term disabilities related to TBI in 407 patients. The authors found that 5 years after injury 64 of the patients had died and 36 were lost to followup. Of those who sustained severe head injury, 56% died, and 50% of the survivors were disabled. The authors note that “head injuries induce long-lasting handicap in 9 per 100,000 habitants which is severe in 2 per 100,000.”
The Canadian Study of Health and Aging (CSHA) is a population-based cohort study designed to assess the prevalence and incidence of dementia and risk factors for it in the Canadian population. Planned originally in 1989, the CSHA includes people 65 years old and older sampled from 36 communities around the country. The study population was selected to be representative of the general population (Lindsay et al., 2002).
The study was conducted in three phases: CSHA-1 in 1991–1992, CSHA-2 in 1996–1997, and CSHA-3 in 2001–2002 (studies of which were not directly applicable to this report). Initial contact with study participants was made by telephone, and they were asked questions